20149 has 2 divisors, whose sum is σ = 20150. Its totient is φ = 20148.

The previous prime is 20147. The next prime is 20161. The reversal of 20149 is 94102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16900 + 3249 = 130^2 + 57^2 .

It is a cyclic number.

It is not a de Polignac number, because 20149 - 2¹ = 20147 is a prime.

Together with 20147, it forms a pair of twin primes.

20149 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10074 + 10075.

It is an arithmetic number, because the mean of its divisors is an integer number (10075).

2²⁰¹⁴⁹ is an apocalyptic number.

It is an amenable number.

20149 is a deficient number, since it is larger than the sum of its proper divisors (1).

20149 is an equidigital number, since it uses as much as digits as its factorization.

20149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 20149 is about 141.9471732723. The cubic root of 20149 is about 27.2114174962.

It can be divided in two parts, 20 and 149, that added together give a square (169 = 13²).

The spelling of 20149 in words is "twenty thousand, one hundred forty-nine".